Problems with Infinity Prelude MTS mid-range

I've had problems with the sub amps (have 6 prelude subs & 3 intermezzo subs,very similar amps) All but 2 have had the amps stop working, & one has hum issue. Repair shops have no incentive to repair, as reimbursement for warranty work is very low. I've rewired & using crown amps with a velodyne sms-1 to power/eq (also a few velodyne sc 1250's power amps)

I also have a problem with a distorting midrange when playing certain CDs (for instance Louis Armstrong, his voice sounds awful, and some rock CDs).
I have been playing them pretty as probably the former owner also did.
No problem with the subs, although they sound not as powerful as they should be, but maybe i am expecting too much.
A rep from Harmon said one could press on the cone lightly and listen for scraping sound, then press some more back and forth and the sound would get better for a while at least. I have not tried it. He didn't mention why the problem was there, but hinted at overdriving.
I don't know what to do, the info here makes me feel I might as well buy a new set of speakers (and keep the subs).
Any tips are welcomed! (I live in Europe.) The speakers sound really good when on a lot of material (jazz, classical).

According to this page, the 3.5 inch driver is no longer available!

http://www.harmanaudio.com/search_browse/partlist.asp?BrandId=INF&MarketId=HOM&Parts=PMTS-TOWER

What to do? Does anyone know of a similar speaker if one would try to replace it?

Magalmros:
I'd look for an extra pair of towers for replacement parts, because you're not going to find a pair of speakers as good as the Prelude MTS for the price of an extra pair of towers.

Drivers are now available as of 31 OCT 2010 according to Harman page:
http://www.harmanaudio.com/search_browse/partlist.asp?BrandId=INF&MarketId=HOM&Parts=PMTS-TOWER

Anyone knows if these are better than the original versions?

/Magnus